Energy storage systems may comprise a number of battery building blocks (BBBs) which are connected together to form a battery and which are controlled by a battery management system (BMS).
It is known to charge batteries in energy storage systems directly using an external charger in order to provide the desired voltage and current profile for the actual battery chemistry used. In a series circuit, a charging current supplied from the external charger positive terminal passes through the battery building blocks of the energy storage system and exits to a charger negative.
However, the overall charge capacity of the ESS is equal to the lowest capacity BBB, multiplied by the number of blocks, as the charging process stops once the BBB with the lowest capacity reaches full charge. Therefore, in cases where one BBB has significantly reduced capacity with respect to the other BBBs in the ESS, the overall capacity of the ESS is greatly reduced and much of the capacity of healthier BBBs may go unused.
Hot swapping is a terms which is used to describe the replacement of electronic components without shutting down or having a significant interruption in the system in which they operate. Hot swapping is used whenever it is desirable to change the configuration, replace components or repair a system without interrupting its operation.
It is known to provide hot swapping in ESSs by having multiple BBBs, for example, by including double (1+1) or multiple (N+1) batteries to provide a suitable level of redundancy. Known prior art frequently presents the traditional redundancy and hot-swap replacement principle where two or more independent modular batteries work in parallel and replacement of a battery module is achieved by switching off the battery which contains the module which is to be replaced while the others provide the power
It is an object of the present invention to provide an improved Energy Storage System.